A bit of topic.
For video editing you should really use a Mac, since the best software for that is Final Cut pro.
You can TODAY make HD-DVDs in DVD studio pro. This is the same program that the most DVD companies use for making DVDs.
When you do videoediting, you need a lot off different disks. Disk for scratch, audio, video, autorendering and so on. If you want to use uncompressed video, you really need something like 6x500gig stipe set to work from.
Buy a powermac.
The four processor powermac is the fastest PC there is for videoediting.
Buy a PCI-E SATA card and hook on external SATA disks.
I have in my powermac 6 internal disks, 4 external SATA and 3 firewire.
The videografic card is not that importent in Windows, but if you have a mac, the whole windows system is 3D and accelerated in the card. At least a Nvidia 7800 should you have.
Also for HD:
You need a real display. I use the Apple Cinema HD. 2580x1600.
On the new powermac you can put in 4 dual link DVI grafic card and connect 8 of these.
(and yes. The Powersupply is 1000watt on the P-mac)
I have been working with videoedition since 1997.
I switched from PC to Mac 2002, when Apple got a "real" os.
You should consider it.
Sorry for shaky ABBA-enlish. Live in Sweden